Patent DE-102011102829-A1 (DE)
Title: Locking device, useful for preventing insertion of reverse gear of gearbox of motor vehicle, comprises locking part arranged in housing, where locking part is movable in housing between first and second positions
IPC: F16H63/34
Filed: 2011-05-30
Abstract: The locking device comprises a locking part (2) arranged in a housing (1). The locking part: is movable between a first and a second position; is movable in the housing in an axial direction; follows the movement of a core part (3); prevents the movement of a transmission part (15) of a gearbox in the first position; and permits the movement of the transmission part of the gearbox in the second position. The core part is movable in the axial direction by an electromagnet assembly arranged in the housing. The housing comprises a sensor for displaying a reverse gear of the gearbox. The locking device comprises a locking part (2) arranged in a housing (1). The locking part: is movable between a first position and a second position; is movable in the housing in an axial direction; follows the movement of a core part (3); prevents the movement of a transmission part (15) of a gearbox in the first position; and permits the movement of the transmission part of the gearbox in the second position. The core part is movable in the axial direction by an electromagnet assembly arranged in the housing. The housing comprises a sensor for displaying a reverse gear of the gearbox, a first housing portion, and a second housing portion that extends radially in the axial direction adjoining the first housing portion. A winding of the electromagnet assembly surrounds the core part. The electromagnet assembly and the locking part are arranged in a chamber of the housing tightly protected against contamination. A control unit having a circuit board is arranged in the chamber and connected with the sensor of the housing for the detection of an output signal. The chamber is sealed tight at a side facing away from the sensor by a sealing member. The locking part and the core part are designed in a tubular shape, and are arranged on a tubular support member. The locking part is arranged in the first housing portion, and is movable into the second position through an opening of the first housing portion. A compression spring is provided between the locking part and an outer wall of the first housing portion, and biases the locking part against the core part. One end of the compression spring is supported on the first housing portion, and an other end of the spring is supported on the locking part. The core part and a member supporting the winding of the electromagnet assembly are arranged in the second housing portion. The winding support member is supported on a shoulder (23) arranged between the first and second housing portions via an annular seal. The locking part and the sensor are connected with an insertable unit that is supported on a support bar, the circuit board and the electromagnet assembly in the chamber such that a sealing of the chamber is arranged between the sealing portion and the insertable unit. An electrical connection is sealed by the sealing member extending outwardly. The sensor is an eddy current sensor in which the electromagnet assembly facing away from the carrier part is disposed. A magnetic field is generated by the eddy current sensor. A signal, indicating the reverse gear location in a position engaged in the carrier part, is generated due to an eddy current effect when the metallic transmission part is moved by the magnetic field, where a signal line runs through the support bar for the circuit board. The electromagnet assembly comprises an annular metal member that comprises a bridge for the magnetic flux existing between the housing, second housing portion and/or the core part.